Disk drives include disk drive suspensions for supporting read/write heads over information tracks of rotating disks. The well-known and widely used Watrous-type suspensions include a load beam having a mounting region on a proximal end, a flexure on a distal end, a relatively rigid region adjacent to the flexure and a spring region between the mounting region and the rigid region. An air-bearing slider that includes a read/write head is mounted to the flexure. The mounting region is typically attached to a base plate for mounting the load beam to an actuator arm. A motor which is controlled by a servo control system rotates the actuator arm to position the read/write head over desired information tracks on the disk. This type of suspension is used with both magnetic and non-magnetic disks.
Disk drive manufacturers continue to develop smaller yet higher storage capacity drives. Storage capacity increases are achieved in part by increasing the density of the information tracks on the disks (i.e., by using narrower and/or more closely spaced tracks). As track density increases, however, it becomes increasingly difficult for the motor and servo control system to quickly and accurately position the read/write head over the desired track. The use of head suspensions having microactuators or fine tracking motors has been proposed to overcome these problems. Such suspensions are disclosed in U.S. Pat. Nos. 5,657,188 and 5,898,544, which are assigned to Hutchinson Technology Incorporated, the assignee of the present application, and which are incorporated by reference herein.
However, the signals that are used to control the microactuators are relatively large (for example, having a peak voltage of about 30 V) compared to the sensitive signals (typically in the millivolt range) coming from the head slider. Since the microactuator control conductors (which conduct microactuator control signals between microactuator control circuitry and the microactuator) and the head slider conductors (which conduct the head slider signals) are typically routed near each other along at least a portion of the load beam, the larger microactuator control signals will tend to capacitively couple into the head slider signals. This crosstalk interference will tend to corrupt the sensitive head slider signals.
One known approach to reducing crosstalk interference between two signal-carrying conductors formed on a substrate that is used in a wide range of electrical applications is to form a conventional passive guard trace (sometimes referred to herein as a "passive crosstalk attenuation conductor") in between the two signal-carrying conductors. The conventional passive crosstalk attenuation conductor is a conductor which is grounded, unterminated, or match terminated at its ends and runs between the two signal-carrying conductors. The conventional passive crosstalk attenuation conductor reduces the coupling between the two signal-carrying conductors, which reduces crosstalk interference therebetween.
Although conventional passive crosstalk attenuation conductors can reduce crosstalk interference to levels that are acceptable for some applications, conventional passive crosstalk attenuation conductors may not reduce crosstalk interference to acceptable level in other applications, such as when used on head suspensions having microactuator control conductors and head slider conductors. Thus, there is a continuing need for greater reductions in crosstalk interference between microactuator control conductors and head slider conductors.